Railway signal system



Nov. 4 1924- R. J. HEWETT RAILWAY. SIGNAL SYSTEM Filed Nov. 12, 1921 5 Sheets-Sheet 1 (J rz A TTORNEYS.

Nov. 4 '1924. 1,514,212

, R. J. HEWETT RAILWAY SIGNAL SYSTEM Filed Nov. 12. 192] 5 Sheets-Sheet 2 v INVENTOR.

A TTORNEYJ NOV. 4 9

1,514,212 R. J. HEWETT RAILWAY S IGNAL SYSTEM Filed Nov. 12 192] 5 Sheets-Sheet 5 -INV ' BY Wm ATTORNEYS,

Nov; 4 1924.

1,514,212 R. J. HEWETT RAILWAY SIGNAL SYSTEM 5 Sheets-Sheet 4 Filed NOV. 12 192] INVENTO ATTORNEYS.

Nov. 4 1924.

R. J. HEWETT RAILWAY SIGNAL SYSTEM Qm vk BE w INVENTOR.

ATTORNEYS,

Patented Nov. 4, 1924.

is l liii iiilfi STATES ROBERT J. OF W'ES'I'IFIELD NEW' JERSEY.

BAELWAY sic-nan SYSTEM.

Application filed. November 12, 1921. Serial No. 514,493.

.7 (1/? .0750122. 2T1? may concern:

Be it known that 1, ROBERT J. l-inwn'rr, a citizen of the United States, residing at lVestfield, in the county of Union and State 5 of New Jersey, have invented certain new and useful Improvements in Railway Signal Systems, of which the following is a full, clear, and exactdescription.

This invention relates to automatic railway block signal systems of the absolute-permissive type i. e., of the type in which a train entering a stretch of track in one di rection will absolutely prevent the clearing of signals governing traffic through the stretch of track in the opposite direction, and at the same time will operate to permit another train to follow said train at the usual distance through said stretch oftrack.

An object of my invention is to provide a normal danger type of such a system. Other general objects are simplicity of arrangement and reliability of operation. Still other objects and advantages of my invention will appear from the following detailed description.

In accordance with my invention I provide selectively acting clearing devices which will clear all the signals in advance of a train in the running direction in a road block between two passing stations and alsothe inlet signal at the next passing station but will not clear the signals governing traffic in the opposite direction in the rear of the train; which will cut out the absolute control at the intermediate signals and the overlap control at passing stz'itionsand wli icli will also provide for a preliminary overlap for the road block control. My invention also comprehends in connection with such a system, indicating devices at the passing stations for indicating the presence of an approaching train on the roadway in a position to clear the signals in the running direction over the stretch of single track between passing stations. It further provides for the manual as well as automatic control of the holding circuits of the clearing relays of'the absolute signals governing entrance to the stretch of single track.

In the preferred embodiment the selectively acting clearing device is operated by means of normally energized track and line relays and normally deenergized clearing relays and signal operating motor circuits. The normally open clearing relay at the sigs nal next in advance of a train is energized by deenergizing the line relay for the eppe site direction at said next signal and when so energized it closes the motor circuit" and clears the signal for the running direction; This directional operation of the line clearing relays is repeatedat each intermediate signal within the road block and results in the clearing of all signals intliei'unning direction in advance of the train. The in vention also comprises certain details" and arrangements which will be pointed out iii the following description of an embodiment of the invention and in the'appen'ded claims; Fig. 1 shows the normal condition of" the circuits and signals for a portion of a road block from passing station "X to passing'sta tion Y.

Fig. 2 shows the circuits and signals for passing station Y and also a westbound train E in track section TlOtlwhich shows the clearing actionfor clearing "west bound, inlet signal 111 to its 45 or cautionary posi tion.

Fig. 2 is a similar view showing the action when the train is in the track section T110 7 Figs. 2 and 1 taken together show the circuits and signals in the road block from passing station X to passing station Y in their operative condition and westbound signals 113, 115 in their 90position' and inlet signal 117 at passing station X was 4:5 or cautionary position. This position is due to the presence of a west bound train E in track section T112, the cautionary position of signal 117 is similar to that of signal 111 in Fig. 2 and both will be'explained in full detail further on. i Referring to Fig. 1 which shows the cir cuits and signals for one half of passing station X and the greater part of the road block between passing station X in Fig. 1 and passing station Y in 2. Thetrack between east bound absolute signal 116 and west bound intermediate signal 115 is composed of two track sections T116 and T115,each' provided with track batteries T15 116 andTB11'5 at their adjacent ends and with track relays R116 at signal 116 and R115 at signal 115. This two section arrangement is atypical layout for track circuits; one track section only may be used when 00111 61118111}. other blocks may be similar. I l Track section T117 with, track battery TB117 and track relay R117 forms one half of the block for passing station X.

The normally closed line circuit for east bound absolute signal 116 is as follows. From common wire 0, line relay L116, wire 1, contact 2 of track relay R116, line wire 3, normally closed circuit controller 4 operated by normal danger west bound intermediate signal 115, wire 5, contact 6 of track relay R115, wire 7, back contact 8 of normally dcenergized east bound clearing relay C114, wire 9, absolute contact 10 of east bound line relay L114, wire 11, negative pole changer N, wires 12, 13, battery M13114, wires 14, 15, positive pole changer P and common wire 0 back to east bound line relay L116 at signal 116.

In tracing this circuit it is seen that pole changers P, N, of east bound signal 114 are in their reverse or negative position which is due to the fact that signal 114 is a normal. danger signal. Battery M13114 therefore supplies a negative current to line wire 3 and to east bound line relay L116 at signal 116, and this causes line relay L116 to be energized in a negative or reverse magnetic condition which holds its polar contact 27 open as shown. The system being a normal danger signal system this statement applies to all pole changers.

The normally closed line circuit for east bound intermediate signal 114 is as follows: From common wire 0, line relay L114, wire 1, contact 2 of track relay R114, line wire 3, contact 4 of track relay R113, wire 5 back contact 6 of east bound clearing relay C112, wire 7, contact 8 of track relay R112, wire 9, wire 10, negative pole changer N, wires 12, 13, battery Mb112, wires 14, 15, positive pole changer P, and common wire 0 back to line relay L114 at signal 114. It will be noted that in this case line relay L112 does not control the line circuit just traced for signal 114. Contact 8 of track relay R112, however, does cont ol it and this control is termed the overlap. That is signal 114 is controlled by track sections T114, T113 as usual and also by track section T112 which is one track section beyond east bound signal 112 which is half way through passing station Y. This overlap track section T112 for east bound intermediate signal 114 may also be termed the preliminary or clearing overlap, its purpose being to enable a west bound train in track section T112 at passing station Y to clear the west bound signals 113, 115 and 117 in advance of the west bound train. This is one of the new features of the invention and will be shown more fully further on. .The normally closed line circuit for east bound inlet signal 112 at passing station Y is as follows: From common wire 0, line relav L112, wire 1. contact 2 of track relay R112, line wire 3, contact 4 of track relay R111, wire 5, back contact 6 of east bound clearing relay C110, wire 7, contact 8 of track relay 11110, wire 9, wire 10, negative pole changer N, wires 12, 13, battery M13110, wires 14, 15, positive pole changer P and common wire 0 back to line relay L112 at signal 112. The circuit just traced has overlap control by contact 8 of track rel-ray M 110 which thereby overlaps one track section, T110, beyond east bound absolute signal 110. This overlap track section T110 for east bound signal 112 may also be termed the clearing overlap, its purpose being to enable a west bound train in track section T110 to clear west bound absolute signal 113 to its 45 position and west bound inlet signal 111 to its 90 position. I

The corresponding control circuits for west bound signals 111, 113, 115 and 117 are similar and are designated by a separate set of numerals. The normally closed line circuit for west bound inlet signal 111 at passing station Y is as follows: From common wire 0, line relay L111, wire 51, contact 52 of track relay R111, line wire 53, contact 54 of track relay R112, wire 55, back contact 56 of west bound clearing relay C113, wire 57 contact 58, of track relay R113, wire 59, wire 60, negative pole changer N of west bound signal 113, wires 62, 63, battery M13113, wires 64, 65, positive pole changer P and common wire 0 back to line relay L111 at signal 111. t

The normally closed line circuit for west bound absolute signal 113 is as follows: From common wire 0, line relay L113, wire 51, contact 52 of track relay R113, line wire 53, normally closed circuit controller 54 operated by normal danger east bound intermediate signal 114, wire 55, contact 56, of track relay R114, wire 57, back contact 58 of normally deenergized west bound clearing relay C115, wire 59, absolute control contact 60 of west bound line relay L115, wire 61, negative pole changer N, wires 62, 63, battery M13115, wires 64, 65, positive pole changer P and common wire 0 back to west bound line relay L113 at signal 1.13.

The normally closed line circuit for west bound intermediate signal 115 is as follows: From common wire 0, line relay L115. wire 51, contact 52 of track relay R 115, line wire 53, contact 54 of track relay R116, wire 55, back contact 56 of west bound clearing relay C117, wire 57, contact 53 of track relay R117, wire 59. wire 60, negative pole changer N, wires 62, 63, battery M13117, wires 64, 65, positive pole changer P and common wire 0 back to line relay L115 at signal 115. It will be .noted that in this case line relay L117 does not control the line circuit just traced for signal 115, contact 58 of track relay R117, however does control it, and this control is termed the overlap. That is signal 115 is controlled by track sections T115, T116, as usual and also by track section T117 that is, one track section beyond signal 117, which is half way through passing siding This overlap control for west bound signal 115 may be termed the clearing overlap circuit. its purpose being to enable an east bound train in track section T117 at passing station X to set the route east bound, that is clear the east bound signals 116, 114 and 112 in advance of the east bound train: This is a new feature of the invention and will be explained further on.

It will be noted that the control circuit for west bound absolute signal 113 is interlocked with east bound intermediate signal 111; this interlocking is effected by the normally closed circuit controller 1 operated by signal 114:. This interlocking insures that west bound absolute signal 113 cannot be cleared unless east bound intermediate signal 114i is in its normal danger position. This interlocking is a well known safety feature of normal danger signaling.

In the same way east bound absolute signal 116 is interlocked with west bound intermediate signal 115, by means of normally closed circuit controller 4 operated by signal 115 which insures that east bound absolute signal 116 cannot be cleared unless west bound intermediate signal 115 is in its normal danger position.

This interlocking of signals applies only at intermediate signals.

Only two intermediate signals 115 and 114 are shown. Any number may be used when necessary.

The normally closed line circuit for west bound inlet signal 117 at passing station X is only partly shown, the complete circuit is the same as west bound inlet signal 1.11 at passing station Y.

Referring now to Fig. 1. At each passing station, as X, an indicator I116 is provided for giving information to train men on passing track TX as to the free or occupied condition of the road block from passing station. X to passing station Y. This indi cator is controlled by contact 411 of line relay L116. The circuit is as follows: From positive terminal of battery M13116, wire 14, wire 10, contact 411 of line relay L116, wire 42, indicator I116, wire 4-8, wires 12 and 13 back to battery M13116. Line relay L116 being controlled by absolute contact of c: st bound line relay L114 provides through control for indicator I116 from east bound absolute signal 116 to the overlap track section T112 at passing station Y. Indicator I116 is shown in its normal clear condition and this will authorize a train man to throw the switch point-s P117 for the main track and move his train into the main track. In Figs. 2, 2 and 2 are shown similar indicators I113 for west bound absolute signal 113 and I110 for eastbound absolute signal 110,

In Figs. 2 and 2 indicator I110 is in its danger position which is due to the presence of the west bound train E in track section T169 or T116; In Fig. 1 indicator I116 in its danger position due to the presence of west bound train E- in track section T112 Fig. 2

The complete motor circuits for east bound absolute signal 116 are as follows: From battery M13116, wire. 20, normally open contact 21 of east bound clearing relay C116, wire front contact of east bound line relay L116, wire 24, 15 signal operating motor mechanism of signal 116, not shown, wire 25, wires 12, 13 to. battery M13116. This circuit when closed at con tact 21 of east bound clearing relay C116 will clear signal 116 to its 15 position. The 90 operating circuit is as follows: From contact 23 of east bound line, relay L116, wire 26, polar contact 27, when closed, wire 28, 90 signal operating motor mechanism, not shown, and wire 25 to battery M3116 described. as follows: l Vhen east bound signal 114; is in either its position or its position its pole changer I N. will be reversed and battery M13114 will then supply a positive current to line wire 3 and to east bound line relay L116 which will reverse its magnetic condition and close its polar contact 27 and this will clear signal 11.6 to its 90 position as previously explained. The motor operating circuits for all other signals are similar and are designated by the same set of numerals.

The circuit for east bound clearing relay G116 is as follows: From battery M13116, negative wire 13, wire 60, east bound clearing relay (L116, wire 31, back contact 32 of west bound clearing relay C117, wires 33, 3,4, normally open back contact 85 of west bound line relay L117 when closed, wire 36, and positive wire 11 to battery M13116. lVhen an east bound train enters passing station X at the other end, not shown, west bound line relay L117 will be deenergized and its back contact 35 will close this clearing circuit and energize east bound clearing relay C116, which by closing its front contact 21 will close the motor circuitfor east bound signal 116 and clear said signal to its 15 position as previously explained. hen the east bound train is in track section T116 and track relay R116 is deenergized its front contact 2 will open the line circuit for east bound line relay L116 and its back contact 37 will close holding circuit on east bound clearing relayC116 as follows: From battery M13116, negative wire 13, wire 30, east bound clearing relay C116, wire 81, back contact 32 of west bound clearing relay C117, wire 33, wire 38, hand key K116, back contact 37 of east bound line relay 141. i 22if 1itc nmt 21' f east i ed Polar contact 27 will be closer clearin rela C116. now ener ized and a .l a I positive wire 20 to batteryMBllti. This holding ci :cuit will hold east bound clearing relay C116 energized while the east bound train is passing through track sections T116 and T115. The purpose of this holding circuit is to cut out contact 8 of rack relay R116 which 1S the overlap control for inlet signal 118 at the westv end of passing sta- R116 is now out out and track relay R116 separate set of numerals.

does not control the inlet signal 118 in the rear.

The circuit for west bound clearing relay C117 is similar and is designated by a These two normally deenergized clearing relays are interlocked so that one only can be energized. In the circuit just described for east bound clearing relay C116 it will be noted that its circuit goes through back contact 32 of west bound clearing relay C117 which insures that west bound clearing relay C117 must be normal in order that east bound clearing relay (1116 may be energized.

In the foregoing it will be noted that east bound clearing relay C116 is first energized by back contact 35 of west bound line relay L117 while the east bound train is approaching signal 116 and after the train has passed said signal back contact 37 of east bound line relay 11116 will hold it energized.

The circuits for west bound clearing relays will be explained more fully in the following sections which explain the full operation of the system.

The complete operation of the system may now be explained by taking the movement of a west bound train through passing sta tion Y in Figs. 2, 2 2 and through the main road block from passing station Y to passing station X in Fig. 1

In Fig. 2 the west bound train E in track section T109 by previous actions has deenergized east bound line relay L110 and thus by closing its back contact 7 5 has energized west bound clearing relay C111. the circuit being as follows: From battery M13111, negative wire 63, wire 70, west bound clearing relay. C111, wire 71, back contact 72 of east bound clearing relay C110, wires 73, 7 4, back contact 75 of eastbound line relay L110,

wire 76, and positive wire 64 to battery M13111. This energizes west bound clearing relay C111 as shown and its front contact 21 closes the motor circuit and clears west bound signal 111 to its 45 position only. 71" est bound absolute signal 113 being as yet in normal danger position its pole changers if. P. are normal and battery 11113113 supplies a negative current to line relay 1.1111 and holds its polar Contact .27 open as shown.

111 Fig. 2 the west bound train E is in track section T110 and track relay R110 is deenergized its contact 2 being open will hold open the line wire 3 and eastbound relay L110 will remain deenergized and its back contact 75 will hold west bound clearing relay C111 energized as before.

he presence of the west bound train in track section T110 produces the next clearing action in advance of the train as follows: Track relay R110 being deenergized its contact 8 will open the line wire for east bound line relay L112 which will be deenergized and this by closing its back con tact 75 will energize the next west bound clearing relay C113, and this by closing its front contact 21 will close the motor circuit and clear west bound signal 113 to its 45 position as shown. The next west bound signal 115 being as yet normal danger as shown in Fig. 1 its pole changers P. N. being normal will supply a negative current from battery M13115 to west bound line relay L113 which holds its polar contact 27 open. It will be noted that contact 8 of track relay 11110 is in the overlap control for line relay 11112. Signal 113 being now in its 45 oosition its ,ole chan ers P. 11., i F g are reversed and this will supply a positive current from battery M13113 to west bound line relay L111 and this will close its polar contact 27 and clear signal 111 to its 90 position as shown.

1V hen the train E is in track section T111 track relay R111 being deenergized its contact 52 will open the circuit for west bound line relay 11111. which will put west bound signal 1.11 to danger as usual. Line relay L111 by closing its back contact 77 will now hold west bound clearing relay C111 energized; the holding circuit being as follows: from battery M13111, wire 20. contact 21 of west bound clearing relay C111, wire 22, back contact 77 of west bound line relay L111, wire 78, wire 73, back contact 72 of east bound clearing relay C110, wire 71, west bound clearing relay C111, wire 70, wire 63 to battery M13111. Cut out contact 67 of west bound clearing relay C111 being already closed will cut out overlap contact 58 of track relay R111 and this will permit west bound line relay for west bound signal 109, not shown to clear to its 45 position for a following west bound train.

Track relay R110 will now be energized and the closing of its contact 2 will close the line circuit for east bound'line relay L110 which will be energized'and by opening its back contact 75 will leave westbound line relay L111 in entire control of west bound clearing relay C111. I

Figs. 2 and 1 taken together shows the through actions which clears absolute signal 113 and intermediate signal 115 to 90 and inlet signal 117 at passing station X to its 45 position. These actions are as follows: The west bound train E in track section T112 by deenergizing track relay R112 will open its contact 8 in the overlap control for east bound line relay L114 which will be deenergized and close its back contact 75 and energize west bound clearing relay C115 and this by closing its front con tact 21 closes the 45 motor circuit and clears intermediate signal 115 to its 45 position.

The 45 position of signal 115 changes its pole changers P. N. to its positive position and this supplies a positive current from battery M13115 to line wire 53 and to absolute line relay L118 which will be energized in its positive magnetic condition and will close its polar contact 27 and clear absolute signal 113 to its 90 position as shown.

Immediately following this the deenergized condition of east bound line relay L114 by opening its front contact 10 will deenergize east bound absolute line relay L116 and this by closing its back contact 75 will energize west bound clearing relay C117 and this by closing its front contact 21 will close the 45 motor circuit and clear inlet signal 117 to its 45 position and this by changing the pole changers P. N. to the positive position supplies a positive current from battery M13117 to line wire 53 and to line relay L115 at signal 115 which reverses the magnetic condition of said line relay and closes its polar contact 27 and clears signal 115 to its 90 position as shown.

The entry of the west bound train E into track section T112 at passing station Y has therefore energized west bound clearing relay C115 and cleared west bound interme diate signal 115 to 90, also energized west bound clearing relay C117 at passing station X and cleared inlet signal 117 at passing station X to its 45 position. This eX plains how by similar actions west bound inlet signal 111 in Fig. 2 was previously cleared to its 45 position.

Obviously by adding other intermediate signals similar to signal 115 into the road block all such intermediate signals will be cleared in the same way.

While the west bound train E is in track section T112 track relay R112 by the open condition of its contact 54 will hold line relay Llll deenergized and west bound clearing relay C111 at signal 111 energized. When the train is in track section T113 track relay R112 will be energized and west bound line relay L111 will be energized and this by opening its back contact 77 will release the holding circuit on west bound clearing relay G111 and will berestored to its normal deenergized condition. a I In case there is a following west bound train in the road block on the right adjoining (llig. 2 then the cleenergized condition of east bound line relay L110 and itsback contact 75 will hold westbound clearing .relay C111 energized and this will provide 'for the movement ofthe said following West bound train in the usual way.

In Fig; 1 the continued movement o'fthe west bound train E through the next block on the left that is, from west bound absolute signal 113 to intermediate signal 115 the operation of the circuits in the rear of the train is the same as just explained for the block from inlet signal 111 to absolute signal 113. In Fig. 1 the'continued 1novementof the west bound train E through the block from intermediate signal 115 to inlet signal 117 at passing station X the operation 01" the circuits in the rear of the train is the same as first described. I

Referring now to Figs. 2 and 1, in case of a west bound train movement from passing track TY t0 the road block the train man will be governed by west bound findicator 1113 which being clear authorizes him to throw the switch points P112 for the main track and this by closing the circuit controller Y112, operated by the switch points P112 short circuits and deenergizes the track relay R112 and this by openingits contact 2 opens the line control wire 3 and deen'ergizes east bound line relay L112 and this by closing its back contact 75 willenergize west bound clearing relay C113 and this by closing its front contact 21 will close the 45 motor circuit and clear west bound absolute signal 113 to its"45 position. The opening of contact 8 of track relay R112 will'deenergize eastbound line relay L114 at signal 114 and this'by closing its back contact 75 will energize west bound clearing relay C115 and this by closing its front contact 21 will close the 45 motor circuit and clear west bound signal 115 to its 45 position. The 45 position of signal 115 now changes its polechangers P. N. to their positive position and battery M13115 supplies a positive current to westbound line relay L113 at signal 113 and this positive current will reverse the magnetic conditionof line relay L113 which will close its polar contact 27 and clear signal 113 to its 90 position.

The deenergized condition of east bound line relay 'L114 by opening its absolute contact 10 will deenergize east bound line relay L116 at signal 116 and this by. closing its back contact 75 will energize west bound clearing relay C117 which by closing its front contact 21 will closethe -451notor circuit and clear westbound inlet signal 117 to its 45 position which will change its pole changers'P. N. to their positive position which will supply a positive current from battery M13117 to line wire 53 and to west bound line relay L115 at signal 115 and this positive current will reverse the magnetic condition of line relay L115 and close polar contact 27 and clear signal 115 to its 90 position.

' hrowing the switch points P112 for the main track at passing station Y has therefore cleared west bound signals 113, 115 and 117 in the same way as if the train was in track section T112 as shown in Figs. 2 and 1 The 90 position of absolute signal 113 now authorizes the train on passing track TYtoproceed into the road block where it will be governed by the west bound signals 113, 115, and 117 in the same way as has been explained for previous west bound train movement E as shown in Figs. 2 and 1 Referring now to Fig. 1.

Assume thatit is necessary to move a train from passing track TX'eastward to the main track-section T117, and'then westward through the main track sections of passing station X. The first part of this movement which is from passing track TX to track section T117 is as follows: The trainman will be governed by east bound indicator 1116 which being clear authorizes him to throw the switch points P117 for the main track and this by closing the circuit controller X117 short circuits and deenergizes track relay R117 and this by opening its contact 52 opens the line control circuit for west bound line relay L117 and this by closing its back contact 35 will energize east bound clearing relay C116 and this by closing its front contact 21 will clear east bound absolute signal 116' to its 415 position. Other circuit actions eastward which have already been explained will result in the clearing of signal 116 to its 90 position. The 90 position of signal 116 authorizes the train man to move his train from passing track TX to the main track section T117.

The operating rules should then require the train to move eastward. beyond west bound signal 117 so that the engineinan will face west bound signal 117 so as to be governed by said signal for the westward movement. 7 tion T116 and track relay R116 and line relay L116 will be deenergized. The back contact 37 of line relay L116 being now closed will hold east bound clearing relay C116 energized and this holds the route set for the eastbound movement. This holding circuit is now as follows: From positive wire 20 of battery M13116, front contact 21, wire 22, back contact 37 hand key K116, wire 38, wire 33, back contact 32 of west bound clearing relay The train will now be in track sec- C117, wire 31, east bound clearing relay C116, wire 30, and wire 13 to battery M13116.

In order to provide for the westward movement east bound clearing relay @116 must be deenergized and west bound clearing relay C117 must be energized. For this purpose the trainman will push releasing key K116 which opens the holding circuit just described and release east bound clearing relay C116. lifter this releaseaction the presence of the train in track section T116 and the deenergized condition of track relay R116 and east bound line relay L116 will automatically set the route west bound and clear west bound signal 117 asfollows: Back contact 75 of east bound line'relay L116 being now closed will energize west bound clearing relay C117 and this by closing its front contact 21 will clear signal 117 to its 45 position. The opening of contact 8 of track relay B116 will produce other circuit act-ions Westward which will result in the clearing of west bound signal 117 to its 90 position and the train will then proceed westward governed by signal 117 and other west bound signals as usual.

Considering the case as a whole it will be seen that in Fig. 2 with train E in track section T109 there is only one energized clearing relay C111, in advance of the train and this clears signal 111 to its 15 position. In Fig. 2, with the train E in track section T110 there are two energized clearing relays C111 and G113 in advance of the train and these clear signal 113 to its e15rposition and signal 111 to its 90 position. In Figs. 1 and 2 with the train E in track section T112 there are three energized clearing relays C113, C115 and G117 in advance of the train and these clear signals 113 and 115 to their 90 position and signal 117 to its 15 position; also there is one energized clearing re- ;lay G111 behind the train E which holds the circuit in the rear of the train set for a following west bound train. For this last purpose there will always be one energized clearing relay in the rear of the train while said train is passing through a local block as from signal 111 to signal 113. The selectively controlled clearing in advance and in the rear of a train is therefore the essential feature of the invention.

I claim:

1. In a normal danger absolute permissive automatic block signal system, a. stretch of single track divided into block and track sections, normal danger signals adjacent the junction of the block sections for controlling trafiic in both directions, a. normally closed line relay and a normally open clearing re- 'lay for each signal, a circuit for each clearing relay adapted to be closed upon the deenergization of both the line and clearing relays of the other adjacent signal at the junction of the block sections, line circuits for controlling the line relays, track relays for opening the circuits of the line relays of hoth signals at each end of the single track when a train is in certain track sections entering or leaving the stretch of single track, and motor circuits for each signal controlled hy its line and clearing relays.

2. In a normal danger absolutepermissive automatic block signal system, a stretch of single track divided into block and tract: sections, normal danger signals for controlling trai'iic in both directions through the block sections, a normally open clearing relay and a nori'nally closed line relay for each signal, overlapping line circuits for said line relays, track relays for opening said line circuits when a train is in certain track sections, a circuit for each clearing relay adapted to be closed to clear the signal in advance of a train upon the deenergization of both the line and clearing relays of the adjacent signal governing tral'hc in the opposite direction, and motor circuits for operating each signal and controlled by its clearing relay.

3. In a normal danger absolute permissive automatic block signal system, a. stretch of single track divided into block and track sections, normal danger signals at the junction of the block sections for controlling tra'l'lic in both directions, a normally closed line relay and a normally open clearing relay for each signal, a circuit for each clearing relay adapted to be closed upon the deenergization of the line relay of the other signal at the junction 01. the block sections, lino circuits for controlling the line relays, track relays for opening the circuits of the line relays of both signals at each end or the single track when a train is in certain track sections entering or leaving the stretch of single track, and motor circuits for each signal controlled by its line and clearing relays.

4, in a normal danger absolute permissive automatic block signal system, a stretch of single track divided into block and track sections, normal danger signals at the junction of the block sections for controlling trattic in both directions, a normally closed line relay and a normally open clearing relay for each signal, a circuit for each clearing relay adapted to he closed upon the deenergization ot both the line and clearing relay of the other adjacent signal at the junction of the block sections, line circuits for controlling the line relays, track relays for opening the circuits of the line relays of both signals at each end oi? the single track when a train is in certain track sect-ions entering or leaving the stretch ot single track, a holding circuit for each clearing relay adapted to be closed by the energization of said clearing relay and the deenergization of its corresponding line relay, and motor circuits for each signal controlled by its line and clearing relays.

5. In a normal danger absolute permissive automatic block signal system, a stretch of single track divided into block and track sections, normal danger signals at the junction of the block sections for controlling trafic in both directions, a normally closed line relay and a normally open clearing relay for each signal, a circuiti'or each clearing relay adapted to be closed upon the deenergization of both the line and clearing relays of the other adjacentsignal at the junction 01- the block sections, line circuits for controlling the line relays, track relays for opening the circuits of the line relays of both signals at each end of the single track when a train is in certain track sections entering or leaving the stretch of single track, aholding circuit for each clearing relay adapted to be closed by the energization of said clearing relay and the deenergization of its corresponding line relay, and a. manually operated switch for opening the holding circuit of each clearing relay at the signals governing entrance to the stretch of single track.

6. In a normal danger absolute permissive automatic block signal system, a stretch of single track divided into block and track sections, normal danger signals at the junction of the block sections for controlling trailic in both directions, a normally closed line relay and a normally open clearing relay for each signal, a circuit for each clearing relay adapted to be closed upon the deenergization of both the line and clearing relays of the other adjacent signal at the junction of the block sections, line circuits for controlling the line relays, a holding circuit for each clearing relay adapted to be closed by the energization of the said clearing relay and the deenergization of its corresponding line relay, and motor circuits for each signal controlled by its line and clearing relays.

In Witness whereof, I hereunto subscribe my signature.

ROBERT J. HEVVETT. 

